Means for mounting fan shafts of blowers



Dec. 16, 1952 FIRTH 2,621,850

MEANS FOR MOUNTING FAN SHAFTS OF" BLOWERS 2 SHEETSSHEET 1 Filed Aug. 1, 1947 Dec. 116, 1952 FlRTH MEANS FOR MOUNTING FAN SHAFTS 0F BLOWERS 2 SHEETS-SHEET 2 Filed Aug. 1, 1947 I INVENTOR. DQZ/LdETZ/Z;

Patented Dec. 16, 1952 MEANS FOR MOUNTING FAN SHAFTS OF BLOWERS David Firth, South Bend, Ind., assignor to Dodge Manufacturing Corporation, Mishawaka, Ind, a corporation of Indiana Application August 1, 1947, Serial No. 765,398

7 Claims.

This invention is concerned with the mounting of the fan shaft of a rotary fan blower.

Fan shaft bearings are commonly carried by spiders or supportin cross bars attached to the fan housing. Such a support associated with an air intake opening through which the shaft extends presents an obstruction in front of such opening, in addition to that presented by the bearing itself, which may objectionably restrict intake of air by the blower. With such supports there is apt to be considerable transmission of noise form the bearings and from the fan through the shaft and bearings to the fan housing and ducts leading therefrom, in which the noise becomes amplified.

An object of the present invention is to provide for supporting fan shaft bearings from the fan housing by practicable means of such character as to diminish transmission of noise as aforesaid and to minimize obstruction to entrance of air to the blower. A further object is to provide for the mounting of the fan shaft by bearings and supporting means therefor of light weight but dependable character and of economical construction. Utilization of selfaligning bearings is a further desideratum.

The above indicated objects are accomplished by means exemplified in the accompanying drawings, wherein Fig. 1 is a front end elevation of a blower of one known type having shaft mounting means embodying the invention in one practicable form.

Fig. 2 is a side elevation thereof.

Fig. 3 is a side elevation on a larger scale of the shaft mounting means at the front end of the fan housing, the front end wall of said housing being shown in section.

Fig. 4 is an enlarged section of one of the tierod adjusting nuts of the illustrative structure and the holding bracket therefor against which the nut is tightened.

Fig. 5 is a side elevation of said bracket shown attached to the front end wall of the fan hous ing, said wall being shown in section.

Fig. 6 is a rear elevation of said bracket.

Fig. '7 represents a fragment of the front end wall of the fan housing, showing slot-like openings therein to permit attachment of said bracket, this view and Figs. 5 and 6 being on the same enlarged scale.

Fig. 8 is a longitudinal sectional View of a selfaligning bearing utilized in the illustrative structure.

In the drawings, 1 denotes the shaft of a rotary fan 2 mounted in a sheet-metal housing 3 of conventional type. The fan housing has in its front end wall an air intake opening 4 of large diameter, and in this instance a similar opening is provided in the opposite end wall of said housing. The blower selected for illustration employs a fan in the form of a paddle wheel whose vanes are carried by a medial disk fixed on the fan shaft, which construction is well known and is not shown. The perimeter of the fan is indicated by dotted lines at 2 in Figs. 1 and 2. As the fan rotates, air is drawn into its opposite ends through said intake openings and is expelled from the periphery of the fan into the surrounding space in the fan housing, which space gradually enlarges to a tangential discharge passage having its outlet at 5.

The fan shaft 1 extends centrally through the air intake openings 4 of the fan housing and is mounted adjacent to said openings in bearings suspended from the fan housing. Self-aligning lubricated bearings of small overhead diameter are desirable. Such a bearing is shown in longitudinal section in Fig. 8. It comprises a balltype bearing unit fitted in a sheet-metal housing 6 in which the unit is capable of slight rocking motion for self-alignment with the shaft. Said unit comprises an annular member I of the two inside diameters in which is press-fitted a porous bushing 8 of two corresponding outside diameters, which member and bushing form between them an annular oil chamber of small radial thickness containing an oil absorbent and conducting wick 9, the end walls of said chamber being formed one by the larger diameter portion of the bushing 8 and the other by the smaller inside diameter portion of the annular member 1 in which the bushing is fitted. Oil is supplied to the wick from an oil cup l6 fitted in an annular boss H on the spherical part of the member I. Said boss extends through an opening in the bearing housing 6 of sufficient diameter to allow limited ball motion of the bearing unit. As the shaft rotates in the bearing, oil feeds by capillary action through the pores of the bushing to the shaft to maintain necessary lubrication, the feed of oil being very miserly, so that after the wick is saturated and the oil cup filled with oil the bearing will remain lubricated for a long time.

The bearing housing 5 is preferably a onepiece seamless sheet-metal stamping of tubular or annular form into which the ball-type bearing unit can be inserted from the rear end of said bearing housing. It is shown having a contracted fore end; which is interiorly spherical to fit the front half of the spherical surface on the member I, and is indented at three points to provide inwardly protruding portions I2 engaging the rear half of said spherical surface. The balltype bearing unit can be forced into place in said bearing housing, whereupon said inwardly Drotruding portions I2 snap into engagement with the rear half of said spherical surface of the member I. It will be understood that the three inwardly protruding portions I2 of the bearing housing are suitably angularly spaced to cooperate with the interiorly spherical fore part of said housing to hold the bearing unit properly fitted for ball movement in the bearing housing.

Said bearing housing 6 is shown formed with a radially extending flange I3 having apertured portions providing ears for attachment of the tie-rods now to be referred to.

Each shaft bearing of the illustrative structure is supported from the fan housing by radiating tensioned wires I4 connected at their inner ends to the bearing housing 6 and at their outer ends to the adjacent end plate of the-fan housing at points outside of the periphery of the air intake opening 4 therein. As shown, the wires I4 have their inner ends formed as hooks engaging in the apertures of the flange I3, said hooks having their ends formed with buttons so that after the wires have been strung through said apertures they cannot become accidentally detached. The wires have screw-threaded outer end portions engaged by nuts I5 supported from the housing by brackets I6 and adapted to be tightened against said brackets for tensioning the wires. Thus the wires so connected constitute tie-rods of small diameter, adjustable in length by manipulation of the nuts, and incapable of transmitting outward thrust.

For supporting each'shaft bearing, the illustrative structure employs three such tie-rods I4 uniformly angularly spaced and arranged as shown, whereby the weight of the bearing and load'there on is sustained by the uppermost tie-rod, hanging vertically from a point directly over the longitudinal center of the bearing, --while the several tie-rods, being appropriately adjusted and tensioned, cooperate to hold the bearing firmly in properly centered position. Though more than three such tie-rods could be employed, suitably angularly spaced and arranged to suspend the load by certain of said rods and to hold the bearing housing in substantially fixed relation to the fan housing by the several tensioned rods, the use of only three such rods arranged asshown is especially advantageous for practicability and minimum expense of contruction.

While the bearing supporting structure thus provided is practically or nearly rigid, yet it possesses a degree of resilient flexibility advan tageous for cushioning and dampening shaft vibration, while preventing substantial oscillation of the bearing.

The tie-rods I4 are preferably of resilient steel wire of high tensile strength. Such wires of diameters of from to A are appropriate, unless in the case of a very large blower having a fan and shaft of such weight as to render it expedient to use wires of somewhat thicker gauge for load suspension.

The nuts I5 are shown as cylindrical nuts rotatably fitted in the brackets I6 and having enlarged heads bearing against said brackets. which heads may be provided with slots for engagement by a screwdriver or appropriate tool for tightening the nuts. In embodiments of the invention for blowers of ordinary sizes, the nuts are fairly small and obtainable as inexpensive articles from nut manufacturers. Inexpensive nut-holding brackets attachable to the fan housing without rivets or screws are provided in the illustrative structure. An individual bracket is shown on an enlarged scale in Figs. 5 and 6. This is a sheet-metal angle bracket providing an outer shelf portion II against which the nut head bears and an inwardly extending brace portion I8. Registering circular holes are cut in said shelf and brace portions to provide a bore in which to fit the nut. The shelf portion IT has at its rear end an upturned tongue I9, and the brace portion I8 has a tongue 20 extending from its rear end. As shown in Fig. 7, the fan housing wall to which the bracket is attached has slot-like openings I5} and 20 To attach the bracket, it is held in a position with its shelf portion parallel with said wall to permit insertion of the tongue I9 in the slot I9. The bracket is then turned through a ninety degree angle to the position shown. As it is turned to said position, the tongue 20 enters the opening 20. It will be observed that when the bracket is in the operative position shown, it is hooked to the fan housing wall by the tongue I9 and that the bracket shoulders 2| and 22 bear against said wall, so that the bracket is firmly supported and well adapted to sustain the load transmitted thereto by the associated tie-rod.

Advantages of the described mounting means will be readily apparent. It provides a light weight but sturdy and highly practicable construction. It is flexible to allow self-alignment of the shaft bearings with the shaft. The bearings utilized and the supporting means therefor are of substantial advantage for practicable and economical construction. Such supporting means presents minimum obstruction to passage of air to the blower. And, because of the character of the construction and the very small diameter of the tensioned tie-rods in relation to their length, the noise transmitted from the bearings and from the fan through the shaft and hearings to the fanhousing is greatly diminished, as compared with the noise so transmitted in many prior art constructions of the kind hereinbefore indicated.

It will be understood that the invention is not intended to'be limited to the particular form of embodiment thereof shown and described.

In the following claims, the clause bearing housing having a bearing for the shaft therein, or equivalent clause, is intended to be construed broadly enough to apply to a bearing consisting of a bored member lined by a bearing bushing, such member in that case being commonly referred to as the bearing housing, and, in the case of a self-aligning bearing, being commonly-referred to as the inner housing as distinguished from an outer housing havinga ball-type bearing unit mounted therein.

I claim:

1. In a blower comprising a rotary fan and a fan housing having a vertical end wall provided with an air intake opening of large diameter through which the fan shaft extends, means for supporting said shaft adjacent to said opening comprising a bearing housing having a bearing for said shaft therein and radiating tie-rods by which said bearing housing is connected to and supported from the fan housing, said tie-rods being in a common vertical plane closely adjacent to and parallel with said end wall, said rods having screw-threaded outer end portions, nuts engaging said screw-threaded portions, and individual nut-holding brackets aifixed to said end wall and against which said nuts are tightened for tensioning said rods.

2. For use in a blower comprising a rotary fan and a fan housing, means to provide a support for the fan shaft thereof comprising a bearing housing having therein a bearing for such shaft, tie-rods of small diameter adapted to be connected to and arranged radiating from said bearing housing and having screw-threaded outer end portions, cylindrical nuts engaging said screw-threaded portions and having heads of enlarged diameter, and sheet-metal angle brackets adapted to be afiixed to the fan housing in which said nuts are rotatably mounted and against which they can be tightened for tensioning said tie-rods, said brackets having outer portions providing seats for said heads and inwardly extending brace portions and said outer and brace portions having registering circular holes in which the nut shanks are rotatably fitted.

3. For use in a blower comprising a rotary fan and a fan housing, means to provide a support for the fan shaft thereof comprising an annular ball-type bearing unit, a bearing housing in which said unit is fitted and capable of ball movement for self-alignment with the shaft, tie-rods of small diameter adapted to be pivotal- 1y connected to and arranged radiating from said bearing housing in a common plane transverse of the axis of said bearing housing, said tie-rods having screw-threaded outer portions, nuts engaging said screw-threaded portions, and individual nut holdings brackets adapted to be aflixed to the fan housing having said nuts rotatably fitted therein and providing seats for said nuts against which they can be tightened for tensioning said tie-rods, whereby said bearing housing can be connected to and supported from the fan housing in substantially fixed relation thereto by said tie-rods.

4. A means for the purpose and of the description set forth in claim 3 wherein said bearing housing consists of a one-piece seamless tubular sheet-metal stamping into which said ball-type bearing unit can be inserted from the rear end of said stamping, the fore end thereof being contracted and interiorily spherical to fit the front half of the spherical surface of said unit, and said stamping having indented portions engaging the rear half of said spherical surface at three angularly spaced points.

5. In a blower comprising a rotary fan and a 5 fan housing having a vertical end wall provided with an air-intake opening of large diameter through which the fan shaft extends, means for supporting said shaft adjacent to said opening 6 comprising a bearing housing having therein a bearing for said shaft, tie-rods of small diameter connected to said bearing housing and radiating therefrom in a common plane adjacent to and parallel with said end wall, said tie-rods having screw-threaded outer end portions, cylindrical nuts engaging said screw-threaded portions and having heads of enlarged diameter, and individual nut-holding brackets affixed to said end wall having said nuts rotatably fitted therein and providing seats for said heads against which the nuts can be tightened for tensioning said tie-rods.

6. In a blower comprising a rotary fan and a fan housing having a vertical end wall provided with an air-intake opening of large diameter through which the fan shaft extends, means for supporting said shaft adjacent to said opening comprising a bearing housing having therein a bearing for said shaft, tie-rods of small diameter connected to said bearing housing and radiating therefrom in a common plane adjacent to and parallel with said end wall, said tie-rods having screw-threaded outer end portions, cylindrical nuts engaging said screw-threaded portions, and sheet-metal angle brackets affixed to said end wall in which said nuts are rotatably mounted and against which they can be tightened for tensioning said tie-rods, said brackets having outer shelf portions providing seats for said heads and inwardly extending brace portions, said shelf and brace portions having registering circular holes in which the nuts are rotatably fitted.

'7. In a blower according to claim 6, the shaftsupporting means therein described having said shelf and brace portions of said brackets formed with rearwardly projecting tongues and having said end Wall formed with slot-like openings through which said tongues extends, said brackets having at opposite sides of said tongues shoulders abutting against one side of said end wall, the tongues extending from said shelf portions being bent outwardly and cooperating with the opposite side of said end wall to secure the brackets thereto.

DAVID FIRTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 653,518 Martin July 10, 1900 675,375 Davidson June 4, 1901 690,018 Davidson Dec. 31, 1901 1,287,166 Young Dec. 10, 1918 2,268,046 Marker et a1. Dec. 30, 1941 

